A recent significant advancement in the field of combustion is the aspirator burner and method described and claimed in U.S. Pat. No. 4,378,205-Anderson and U.S. Pat. No. 4,541,796-Anderson. This technology enables one to carry out combustion with oxygen or oxygen-enriched air without the very high temperatures and poor mixing characteristics of oxygen combustion, thus achieving combustion without the generation of high levels of nitrogen oxides (NO.sub.x) and without causing local hot spots within the combustion zone. This is accomplished using a defined large distance between the fuel and oxidant injection points and aspiration of furnace gases into the oxidant prior to mixture and combustion with the fuel.
In the combustion of certain materials, such as in the incineration of hazardous wastes, there exists within the combustion zone high levels of nitrogen or nitrogen compounds which can be a source of NO.sub.x when the combustion is carried out. Furthermore certain combustion zones, such as a rotary kiln used for the incineration of hazardous wastes, are relatively long and narrow. While it is known that NO.sub.x formation may be reduced, and more uniform temperature distribution may be attained, by carrying out combustion in a diffuse flame, such a diffuse flame is not achievable in a narrow combustion zone because the flame readily impinges or overheats the walls of the combustion zone.
Accordingly it is an object of this invention to provide a method for carrying out combustion, especially in a relatively narrow combustion zone, while achieving a more uniform temperature distribution and while achieving low NO.sub.x formation even in the presence of significant amounts of nitrogen or nitrogen compounds within the combustion zone.
It is another object of this invention to provide an apparatus for carrying out combustion, especially in a relatively narrow combustion zone, while achieving a more uniform temperature distribution and while achieving low NO.sub.x formation even in the presence of significant amounts of nitrogen or nitrogen compounds within the combustion zone.